Overmolded lead frame providing contact support and impedance matching properties

ABSTRACT

An electrical connector includes first and second adjacent electrical contacts that each define respective first and second mating ends, the first mating end of a first one of the first and second adjacent electrical contacts defines a first contact surface, the second mating end of a second one of the first and second adjacent electrical contacts defines a second contact surface electrically isolated from the first contact surface; and a dielectric material positioned between the first and second adjacent electrical contacts. When a mating connector applies a force to the first contact surface and the second contact surface, the first and second mating ends and the dielectric material all move in a first direction.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to connectors. More specifically, thepresent invention relates to a connector with an overmolded lead framethat includes a web between adjacent contacts.

2. Description of the Related Art

A known connector 100 is shown in FIG. 1. The connector 100 includes ahousing 101 that surrounds contacts 102 that transmit electricalsignals. A portion of the housing 101 in FIG. 1 is cut away to show thebottom row 115 of contacts 102. Although not shown in FIG. 1, theconnector 100 is typically mounted to a printed circuit board (PCB). ThePCB includes traces that transmit electrical signals. The housing 101includes an opening 103 into which, for example, an edgecard can beinserted. The edgecard includes pads that engage with the beams 102 a ofthe contacts 102. The beams 102 a deflect as the edgecard is insertedinto the housing 101, creating a mechanical and electrical connectionbetween the contacts 102 and pads. An edgecard to be used with theconnector shown in FIG. 1 will typically include pads on the top andbottom surfaces that engage with the top row 110 of contacts 102 (notshown in FIG. 1) and with the bottom row 115 of contacts 102. Thecontacts 102 in the connector 100 provide an electrical path between thepads of the edgecard and the traces in the PCB.

FIG. 7 shows the contacts 102 from the bottom row 115 of the connector100 shown in FIG. 1. The contacts 102 in FIG. 7 are in an open-pin-fieldarrangement in that the contacts 102 can be assigned differentfunctions, including, for example, as signal contacts, i.e., a singlecontact for single-ended signals or a pair of contacts for differentialsignals, or as ground contacts, i.e., contacts connected to ground. Inhigh-speed applications, adjacent contacts 102 can be paired together totransmit a differential signal. The adjacent differential pairs ofcontacts 106 can be separated by a ground contact 107. The shape of thecontacts 102 in FIG. 7 is determined by mechanical considerations andnot by signal integrity considerations.

As electrical signals are transmitted between the pads of the edgecardand the traces in the PCB, the electrical signals may experiencedegradation in signal integrity due to the changing transmission lineimpedance along the signal path. As shown in FIG. 2, the connector 100includes an insulating, dielectric plastic wall 104 between adjacentcontacts 102 to avoid shorting of adjacent contacts 102. The dielectricproperties of the plastic may be chosen to reduce the potentialimpedance mismatch along the length of the contact beam 102 a.

As shown in FIGS. 3 and 4, additional space between the walls 104 andthe contacts 102 is needed for positional tolerances, i.e. so thecontact 102 does not bind against the wall 104 when it deflects to mateto an edge card. This additional space results in a wider air gap 105between the contact beams 102 a and the walls 104. The wider air gap 105between the contacts 102 and the walls 104 limits the ability toimpedance match the transmission line.

As shown in FIG. 2, there is no structure that deflects with thecontacts 102 as the contact beams 102 a are deflected. The tips 102 b ofadjacent contact beams 102 a can spread wider apart or come closertogether during deflection, which can change the impedance of thetransmission line formed by the contact beams 102 a.

High-speed connectors often include ground planes to separate the signalpaths and to electrically connect the individual ground contacts 107together. FIG. 5 shows the high-speed connector 100 in which adjacentsignal contacts 102 are surrounded by ground contacts 107. The adjacentsignal contacts 102 can be grouped in a differential pair 106 thattransmits differential signals.

FIG. 6 is a sectional view of the connector 100 that shows the top 110and bottom 115 rows of contacts 102. The contacts 102 of both the top110 and bottom 115 rows include a 90° bend and a portion that extendsfrom the 90° bend downward towards a PCB (not shown). The contacts 102of the top 110 and bottom 115 rows can be surface mounted to the PCB,which creates mechanical and electrical connections to pads on the PCB.The pads of the PCB are connected to the traces in the PCB. The contacts102 of the top row 110 of contacts extend out and over the contacts 102of the bottom row 115 of contacts.

SUMMARY OF THE INVENTION

To overcome the problems described above, preferred embodiments of thepresent invention provide a connector that can be used in high-speedapplications, that has improved impedance matching, and that includes amaterial between the contacts that deflects with the contacts.

According a preferred embodiment of the present invention, an electricalconnector includes first and second adjacent electrical contacts thateach define respective first and second mating ends, the first matingend of a first one of the first and second adjacent electrical contactsdefines a first contact surface, the second mating end of a second oneof the first and second adjacent electrical contacts defines a secondcontact surface electrically isolated from the first contact surface;and a dielectric material positioned between the first and secondadjacent electrical contacts. When a mating connector applies a force tothe first contact surface and the second contact surface, the first andsecond mating ends and the dielectric material all move in a firstdirection.

The electrical connector further preferably includes a third electricalcontact positioned immediately adjacent to and edge-to-edge with thesecond one of the first and second electrical contacts. The electricalconnector is preferably devoid of dielectric material between the thirdelectrical contact and the second one of the first and second adjacentelectrical contacts.

Preferably, the first and second adjacent electrical contacts are eachcantilevered with respect to a dielectric wafer housing, and thedielectric material is a web positioned between the first and secondadjacent electrical contacts. The web is preferably cantilevered withrespect to a pivot point adjacent to the dielectric wafer housing suchthat the web also moves in the first direction when a mating connectorapplies a force to the first contact surface and the second contactsurface.

The electrical connector further preferably including a firstdifferential signal pair and a second differential signal pair carriedby a dielectric housing and a ground shield positioned adjacent to thedielectric housing. Preferably, the dielectric housing defines a firstair gap between the first and second adjacent signal contacts of thefirst differential signal pair, a second air gap between third andfourth adjacent signal contacts of the second differential signal pair,and a third air gap between the second signal contact and the thirdsignal contact that exposes the ground shield to air between the secondsignal contact and the third signal contact.

The electrical connector preferably has a differential insertion loss ofless than −1 dB through approximately 1 GHz at frequencies betweenapproximately 1 GHz and approximately 25 GHz. The electrical connectorpreferably has a differential insertion loss of less than −1 dB atfrequencies between approximately 1 GHz and approximately 33 GHz. Afrequency domain near end crosstalk is preferably below −50 dB atfrequencies between approximately 1 GHz and approximately 34 GHz. Afrequency domain near end crosstalk is preferably below −60 dB atfrequencies between approximately 1 GHz and approximately 31 GHz. Afrequency domain far end crosstalk is preferably below −50 dB atfrequencies between approximately 1 GHz and approximately 34 GHz. Afrequency domain far end crosstalk is preferably below −60 dB atfrequencies between approximately 1 GHz and approximately 25 GHz.

The electrical connector further preferably includes an electricalconnector housing. The electrical connector housing preferably does notdefine front ribs between the first and second mating ends of first andsecond adjacent signal conductors.

The dielectric material preferably is cantilevered.

According to a preferred embodiment of the present invention, anelectrical connector includes an electrical connector housing thatcarries first and second adjacent electrical contacts. The first andsecond adjacent electrical contacts each define respective first andsecond mating ends, and the electrical connector housing does not definefront ribs between the first and second mating ends of the first andsecond adjacent signal conductors.

According to a preferred embodiment of the present invention, anelectrical connector includes a dielectric housing; a first electricalcontact carried by the electrically dielectric housing, the firstelectrical contact defines a first contact surface; a second electricalcontact carried by the housing and positioned adjacent to the firstelectrical contact to define a differential signal pair with the firstelectrical contact, the second electrical contact defining a secondcontact surface electrically isolated from the first contact surface;and a dielectric material that extends between the first electricalcontact and the second electrical contact, the dielectric materialextends continuously from a point adjacent to the dielectric housing andterminates prior to the first contact surface.

The dielectric material preferably is a web integrally formed with thedielectric housing. Preferably, when a mating connector applies a forceto the first contact surface and the second contact surface, the firstand second mating ends and the cantilevered dielectric material all movein a first direction. The dielectric material preferably iscantilevered. The dielectric material preferably is cantilevered withrespect to a pivot point adjacent to a dielectric wafer housing.

Preferably, the first and second adjacent electrical contacts eachdefine two opposed edges, the first and second adjacent electricalcontacts are positioned edge-to-edge, and the first and second adjacentelectrical contacts are physically connected to one another adjacent tothe first and second mating ends by the dielectric material.

The electrical connector further preferably includes a dielectric buttonpositioned only between the first and second adjacent electricalcontacts.

According to a preferred embodiment of the present invention, anelectrical connector includes a first differential signal pair and asecond differential signal pair carried by a dielectric housing and aground shield positioned adjacent to the dielectric housing. Thedielectric housing defines a first air gap between first and secondadjacent signal contacts of the first differential signal pair, a secondair gap between third and fourth adjacent signal contacts of the seconddifferential signal pair, and a third air gap between the second signalcontact and the third signal contact that exposes the ground shield toair between the second signal contact and the third signal contact.

The above and other features, elements, characteristics, steps, andadvantages of the present invention will become more apparent from thefollowing detailed description of preferred embodiments of the presentinvention with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cut-out view of a conventional connector.

FIGS. 2-4 are close-up views of the contacts of the connector shown inFIG. 1.

FIG. 5 is a cut-out view of the connector shown in FIG. 1.

FIG. 6 is a cross-section view of the connector shown in FIG. 1.

FIG. 7 is a top view of the contacts used in the connector shown in FIG.1.

FIGS. 8 and 9 are top views of the contacts according to a preferredembodiment of the present invention.

FIG. 10 is a perspective view of a lead frame for a bottom row ofcontacts according to a preferred embodiment of the present invention.

FIG. 11 is a top view of the lead frame shown in FIG. 10.

FIG. 12 is a side view of the lead frame shown in FIG. 10 showingdeflection of the contacts.

FIG. 13 is a front, partial view of the lead frame shown in FIG. 10.

FIG. 14 is a perspective view of a lead frame according to a preferredembodiment of the present invention.

FIG. 15 is a perspective view of the lead frame shown in FIG. 14 filledwith conductive epoxy.

FIG. 16 is a sectional view of the lead frame shown in FIG. 15.

FIG. 17 is a perspective view of the lead frame shown in FIG. 14 filledwith a thin, stamped shield.

FIG. 18 is a sectional view of the lead frame shown in FIG. 17.

FIG. 19 is a front perspective view of a lead frame for a top row ofcontacts according to a preferred embodiment of the present invention.

FIG. 20 is a back perspective view of the lead frame shown in FIG. 19.

FIG. 21 is a top view of the lead frame shown in FIG. 19.

FIG. 22 is a side view of the lead frame shown in FIG. 19.

FIG. 23 is a back view of the lead frame shown in FIG. 19.

FIG. 24 is a front view of a connector according to a preferredembodiment of the present invention.

FIG. 25 is a cut-out view of the connector shown in FIG. 24.

FIG. 26 is a perspective view of a connector according to a preferredembodiment of the present invention.

FIG. 27 is a view of a contact row of a lead frame from the connectorshown in FIG. 26.

FIG. 28 is another view of the contact row of the lead frame shown inFIG. 27.

FIG. 29 is a close-up view of the contact row shown in FIG. 28.

FIG. 30 is a perspective view of a mating connector according to apreferred embodiment of the present invention.

FIG. 31 is a view of a contact row of a lead frame from the connectorshown in FIG. 30.

FIG. 32 is another view of the contact row of the lead frame shown inFIG. 30.

FIG. 33 is a close-up view of the contact row shown in FIG. 32.

FIGS. 34 and 35 are perspective views of a cage assembly according to apreferred embodiment of the present invention.

FIGS. 36 and 37 are close-up perspective views of the contacts of thereceptacle in the cage assembly shown in FIG. 34.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIGS. 8-23 show lead frames according to preferred embodiments of thepresent invention. The lead frames shown in FIGS. 8-18 can be used as abottom row of contacts, and the lead frames shown in FIG. 19-23 can beused as a top row of contacts. The lead frames can be used in anysuitable connector, including a connector similar to the one shown inFIGS. 1 and 5. The lead frames can be used in connectors with housingsthat do not include walls or ribs between adjacent contacts. The leadframes can also be used in the connector shown in FIGS. 24 and 25 thathave ribs between the ground contacts and the pairs of differentialsignal contacts, but not between the pairs of differential signalcontacts. It is possible to use the lead frames shown in FIGS. 8-23 in aconnector with only a single row of contacts. It is also possible to usemore than one lead frame per row of contacts. It is possible to use thetechniques discussed below to tune the impedance of the differentialpairs to have any suitable impedance, e.g. 85±10 Ω, 92±10 Ω, or 100±10Ω.

FIG. 8 shows the lead frame 10 for a bottom row of contacts 12. FIG. 9shows the same lead frame 10 as FIG. 8 and includes the wafer 11connecting the contacts 12 and the web 13 between the contacts 22 of adifferential pair. Reference number 12 generally refers to all contacts,which include ground contacts 23 and contacts 22 in a differential pair.

FIGS. 9 and 10 show that a web 13, made from electrically dielectricplastic, plastic containing magnetic absorbing material, i.e., magneticlossy material, such as ferrite or carbon material at a percentage lowenough to prevent electrical shorting of a differential signal pair, orother similar material, fills at least a portion of the gap between theadjacent contact beams 12 a of the differential signal contacts 22. Thewafer 11 is also be made from materials similar to or the same as theweb. The adjacent contacts 12 defining the differential signal contacts22 are physically connected by the web 13, and the differential signalcontacts 22 are not physically connected by the web 13 to the contacts12 adjacent to but not included in the differential signal contacts 22.The web 13 is preferably made of a dielectric material other than air.For example, the web 13 can be made of a plastic formed by molding, butother suitable materials and methods could also be used to form the web13. The web 13 is movable and flexes in first directions D that are bothtransverse to the mating and unmating directions M.

The lead frames 10 can be formed by stamping the contacts 12 to have adesired shape as discussed above and then forming the wafer 11 byinjection molding. Instead of injection molding, other suitableprocesses, including, for example, dam-and-fill encapsulation, can beused to form the lead frames 10. In dam-and-fill encapsulation, a dammaterial is used to create a dam, and the dam is then filled with anencapsulant that is typically infra-red (IR) or thermally cured orhardened. Because the web 13 can replace the walls between adjacentcontacts 22, positional tolerances between the contacts 22 are relaxed,allowing the adjacent contacts 22 to be moved closer together. Becausethe web 13 between adjacent contacts 22 can be made of a material otherthan air with a dielectric constant of about 3.5, which is higher thanthe dielectric constant of air of 1, it is possible to better impedancematch the contact region with the adjacent transmission lines, such asthose on the PCB. Also, because the adjacent contacts 22 are secured inthe dielectric web 13, the positions between the adjacent contacts 22remain fixed as the adjacent contacts 22 flex while being mated. Bettercontrol of the geometry between all of the contacts 12 reduces thevariation in impedance between the various differential signal pairs inthe connector. The contacts 22 can define contact tips 12 b. A firstcontact tip 12 b may further define a first contact surface 12 d, andthe second contact tip 12 b may further define a second contact surface12 d. The first contact tip 12 b and the second contact tip 12 b may beimmediately adjacent to one another, and the first contact surface 12 dand the second contact surface 12 d may be immediately adjacent to oneanother. The first contact surface 12 d and the second contact surface12 d may physically, electrically, or both physically and electricallycontact a respective mating PCB pad or a respective mating contact of amating connector. The contacts 22 may also define two opposed edges andtwo opposed broadsides, and two adjacent contacts 22 may be positionededge-to-edge or broadside-to-broadside. The web 13 may be positionedbetween the edges or the broadsides of two adjacent contacts 22.

As shown in FIG. 11, the tips 12 b of the contacts 12 can be jogged to alarger or smaller spacing. The spacing of the tips 12 b of the contacts12 should match the spacing between the pads on the edgecard. Largerspacing between the tips 12 b of the contacts 12 corresponds to largerspacing between the pads on the edgecard. The tips 12 b of the contacts12 can be jogged such that the spacing between the tips 12 b or contactsurfaces 12 d of adjacent contacts 12 is the same for each adjacent pairof contacts 22, which allows for the same spacing between adjacent padson the edgecard, which can make the edgecard easier to manufacture. Thejogging of the tips 12 b of the contacts 12 can result in the tips 12 bhaving a higher impedance.

As shown in FIGS. 10, 11, 12, and 13, the web 13 can include a button 14near the tips 12 b of the contacts 12 or between the wafer 11 and thecontact tips 12 b or contact surfaces 12 d (as shown in FIG. 11). Thebutton 14 anchors the web 13 to the contact beams 12 a, allowing the web13 to move with the contact beams 12 a as the contact beams 12 adeflect. The web 13 keeps the adjacent contacts 22 spaced apart at aconstant distance from each other, even when the contact beams 12 a aredeflected. The constant distance between adjacent contacts 22 improvesthe impedance matching. The web 13, button 14, or both can be positionedonly between the first and second electrical contacts 22, and notbetween a third electrical contact immediately adjacent to the first orsecond electrical contacts 22 and either of the first and secondelectrical contacts 22. The electrical connector may be devoid ofmovable, dielectric material, such as web 13 or button 14, between thethird electrical contact and either of the first and second adjacentelectrical contacts 22. The web 13 or button 14 can be attached to thewafer 11 or not be attached to the wafer 11.

In one preferred embodiment, an electrical connector is provided. Theelectrical connector may include first and second adjacent signalcontacts that define a first differential signal pair and a thirdelectrical contact positioned immediately adjacent to, and possiblyedge-to-edge with, the second one of the first and second electricalcontacts. The two first and second adjacent signal contacts are attachedto one another such that when contact tails are fixed by a wafer oranother dielectric housing and a first direction D force is applied toone of the two first and second adjacent signal contacts, a first matingend of the first adjacent signal contact and a second mating end of thesecond adjacent signal contact also move in one of first directions Deven though the first and second adjacent signal contacts are notphysically connected by electrically conductive material and areelectrically isolated from one another along entire physical lengths ofthe first and second adjacent signal contacts. The first and secondmating ends of the first and second adjacent signal conductors can becantilevered with respect to a wafer or an electrically dielectric waferhousing that may be fixed and may carry the first and second adjacentsignal conductors having respective conductor portions fixed withrespect to the wafer or the wafer housing. The contact surfaces 12 d oradjacent contact surfaces 12 d of contact tips 12 b may be oriented tobe coincident with a common plane and not perpendicular to a commonplane. The contact surfaces 12 d or adjacent contact surfaces 12 d ofthe contact tips 12 b may not face or oppose one another. Adjacentcontact surfaces 12 d of two adjacent contacts 22 of a differentialsignal pair may not lie in parallel planes. Movement of the first orsecond adjacent signal contacts occurs even if a force is only directlyapplied to the contact tip 12 b or the contact surface 12 d of the firstadjacent signal contact or even if a force is only directly applied tothe contact tip 12 b or the contact surface 12 d of the immediatelyadjacent second adjacent signal contact. Stated another way, the firstand second adjacent signal conductors are not mechanically independentof each other even though the first and second adjacent signalconductors are electrically isolated from one another. Movement of thefirst and second mating ends, the first mating end, or the second matingend can be in a direction transverse to a mating direction of theelectrical connector with a mating electrical connector, such as amating PCB, mating card edge, or mating electrical contact. The firstand second adjacent signal conductors can be attached to one another bya web that cantilevers from a pivot point positioned adjacent to orintegrally formed with the wafer or other electrically dielectric waferhousing, wherein the wafer or other electrically dielectric waferhousing and the web may be made from an dielectric material or othermagnetic lossy material described above.

In other preferred embodiments, the first and second adjacent signalconductors can be attached to each other by a combination of the web andthe button, by a movable, flexible, or cantilevered dielectric material,commoning band, bar, or member, or any other type of electricallynon-conductive mechanical attachment mechanism that causes the first andsecond mating ends or contact surfaces 12 d of the first and secondadjacent signal conductors and the movable, flexible, or cantilevereddielectric material to all move in same direction at the same time. Thefirst and second mating ends of the first and second adjacent signalconductors can functionally act as a single mating end. The first andsecond adjacent signal conductors and the web can all move in the samedirection at the same time, to keep the impedance of the differentialsignal pair within 1 Ω-10 Ω during mating and unmating of a matingconnector such as a mating PCB, mating card edge, or mating electricalcontact. The first and second mating ends have at least two independentdegrees of freedom of motion. From the commoning member forward, thefirst and second mating ends can move independently of each other inopposite directions assuming equal but opposite forces are applied tothe two adjacent first and second mating ends. If a force is applied tojust one mating end, that mating end will deflect more than the adjacentmating end, but both the first and second mating ends will both move inthe same direction as the force (measured in Newtons, for example)increases.

As shown in FIGS. 12 and 13, the web 13 can include a button 14 on anactive portion of the contact beam 12 a, i.e., a portion of the contact12 that moves when mated with an edgecard. The button 14 anchors the web13 to the contact beams 12 a, allowing the web 13 to move with thecontact beams 12 a as the contact beams 12 a deflect. The web 13 keepsthe adjacent contacts 22 spaced apart at a constant distance from eachother, even when the contact beams 12 a are deflected. The constantdistance between adjacent contacts 22 improves the uniformity of theimpedance between the different signal channels. Importantly, the web 13does not mechanically interfere with mating of the contacts 12 to theedge card.

The dielectric properties of the wafer 11 and the webs 13 can be chosento optimize signal integrity of signals transmitted through theconnector.

Referring to FIGS. 8 and 9, the contacts 12 can be divided intodifferent zones in which the arrangement of the spacing between thecontacts 12 changes because of signal integrity considerations and/ormechanical considerations. In the first zone for the contact tips 12 b,the spacing between adjacent contacts 12 can match the spacing on thepads on the edgecard. Because the tips 12 b of the contacts 12 arestubs, impedance matching is no longer required in this zone. In fact,increasing the impedance in the first zone is desirable to minimize itsinfluence on transmission in the edgecard.

Mated contact between the contact beams 12 a and the edgecard occurs atapproximately the boundary between the first zone and the second zone.In the second zone for the movable contact beams 12 a, the spacingbetween the contacts 22 of a differential pair can be adjusted becausethe web 13, with a higher dielectric constant, is located between thecontacts 22. In the second zone, it is also possible to decrease thespacing between the contacts of a differential pair to increase thecoupling between the contacts 22 of the differential pair and toincrease the spacing between adjacent differential pairs to reducecross-talk between adjacent differential pairs.

The third zone refers to the embedded portion of the contacts 12, wherethe contacts 12 do not move during mating. The spacing between thecontacts 22 of a differential pair can be further increased in this zonebecause this portion of the contacts 22 is embedded in the wafer 11 sothat it cannot move. It is also possible to adjust the impedance byremoving portions of the wafer 11. For example, in FIG. 9, portions ofthe wafer 11 adjacent to the ground contacts 23 can be removed to reducethe coupling between the adjacent differential pairs 22 and the groundcontact 23.

In the fourth zone, the contact beams 12 a are fixed, so the spacingbetween the contacts 22 in a differential pair can be reduced since notolerance for mechanical motion during mating is required. Impedancematching can be controlled by increasing the width of the differentialpair contacts 22. In the fourth zone, it is possible to use air as thedielectric because the freedom in contact beam 12 a geometry allowsimpedance matching without use of a dielectric material.

In the fifth zone of the contact tail 12 c, the widths of the contacts12 are reduced to ensure enough spacing so that the contact tail 12 ccan be soldered to the PCB without shorting together adjacent contacts12.

FIG. 14 shows a bottom view of a lead frame 10. The wafer 11 of the leadframe 10 includes a cavity 20 that extends along the length of the wafer11. The cavity 20 can be filled with a conductive epoxy or a similarhardening conductive material to cast a ground shield 21 as shown inFIGS. 15 and 16. The ground shield 21 can partially surround theadjacent contacts 22. The ground shield 21 can make electrical contactwith the ground contacts 23. The conductive epoxy can be used to shiftthe resonance frequency of the connector. For example, the conductiveepoxy, such as a lossy or magnetic absorbing material, can shift theresonance frequency to above 28 GHz, allowing the connector to haveexcellent signal integrity at this bandwidth.

Instead of a conductive epoxy, a formed metallic or lossy metal,conductive shield 24 can be used as shown in FIGS. 17 and 18. The formedmetallic or lossy shield 24 is preferably a thin, stamped metal orcarbon based polymer, but other suitable materials could also be used toform the formed metallic or lossy shield 24. As shown in FIG. 18, theformed metallic or lossy shield 24 can partially surround the adjacentpairs 22, and the formed metallic or lossy shield 24 can make contactwith the ground contacts 23.

FIGS. 19-23 show a lead frame 30 that can be used as the top row ofcontacts 32. Reference number 32 generally refers to all of thecontacts, which include ground contacts 43 and contacts 42 in adifferential pair. As with the bottom row of contacts 12, the lead frame30 for the top row of contacts 32 can include webs 33 and buttons 34.Also the contacts 32 can be divided into zones. In the first zone forthe contact tips 32 b, the spacing between adjacent contacts 32 can beadjusted to match the spacing on the pads on the edgecard. Because thetips 32 b of the contacts 32 are stubs, impedance matching is no longerrequired in this zone. In fact, increasing the impedance in the firstzone is desirable to minimize its influence on transmission in theedgecard.

When mated, contact between the contact beams 32 a and edgecard occursat approximately the boundary between the first zone and the secondzone. In the second zone for the movable contact beams 32 a, the spacingbetween the contacts 42 of a differential pair can be adjusted becausethe web 33, with a higher dielectric constant, is located between thecontacts 42 of the differential pair. In the second zone, it is alsopossible to decrease the spacing between the contacts 42 of adifferential pair to increase the coupling between the contacts 42 ofthe differential pair and to increase the spacing between adjacentdifferential pairs to reduce cross-talk between adjacent differentialpairs.

The third zone refers to the embedded portion of the contacts 32, wherethe contacts 32 do not move during mating. The spacing between thecontacts 42 of a differential pair can be further increased in this zonebecause this portion of the contacts 42 is embedded in the wafer 31 sothat it cannot move. It is also possible to adjust the impedance byremoving portions of the wafer 31. For example, in FIG. 23, portions ofthe wafer 31 adjacent to the ground contacts 43 can be removed to reducethe coupling between the adjacent differential pairs 42 and the groundcontact 43. Portions of the wafer 31 may also be removed between thedifferential signal pair 42 to improve performance.

In the fourth zone of the contact tail 32 c, the width of the contacts32 is reduced to ensure enough spacing so that the contact tail 32 c canbe soldered to the PCB without shorting together adjacent contacts.

As shown in FIG. 22, the wafer 31 includes a shield 44 locatedunderneath the contacts 32. The shield 44 can be connected to the groundcontacts 43. In this arrangement, the ground contacts 43 and thecontacts 42 of a differential pair can be separated by a combination ofair and portions of the wafer 31.

FIG. 23 shows an approach that is reversed with respect to the first andsecond mating ends of the first and second adjacent signal conductors.In non-mating portions of the first and second adjacent signalconductors, a web of dielectric material is removed or not added betweenthe first and second adjacent signal conductors. Additionally, a web ofdielectric material is also removed or not added between adjacentdifferential signal pairs. In this case, an air dielectric can improveimpedance and crosstalk of the electrical connector, independent fromthe dielectric web positioned between the first and second adjacentsignal conductors, adjacent to the first and second mating ends of thefirst and second adjacent signal conductors.

FIGS. 24 and 25 show a connector 50 that can be used with the leadframes 10, 30 discussed above. The connector 50 includes ribs 52 betweeneach of the ground contacts 43 and the adjacent pair of differentialcontacts 42 and does not include walls between the contacts 42 in eachdifferential pair. The electrical connector housing does not definefront ribs between the first and second adjacent signal conductors orbetween the first and second mating ends of the first and secondadjacent signal conductors. The first and second adjacent signalconductors will not short circuit electrically in the absence of theelectrical connector housing front ribs because the first and secondadjacent signal conductors are separated by the intra-conductor webdiscussed above. The size of the ribs 52 can be reduced such that theribs 52 are only located near the contact tips 32 b. Portions of theribs 52 could also be removed, such as, for example, only leaving therib 52 present near the contact tips 32 b. Another arrangement to raisethe impedance of the contact tips 32 b is to include one rib 52 betweenthe contacts 42 of the differential pair and to not include ribs 52between each of the ground contacts 43 and the adjacent contacts 42 of adifferential pair. This configuration is the opposite of the arrangementshown in FIGS. 24 and 25. This opposite arrangement is substantiallyelectrically equivalent to the arrangement shown in FIGS. 24 and 25, butthe arrangement in FIGS. 24 and 25 provides more ribs 52 for mechanicalmating. The elimination of ribs 52 improves impedance continuityindependently from the air pockets defined adjacent to the non-matingportions of the first and second adjacent signal conductors,independently from the air pockets defined between adjacent differentialcontact pairs, independently of the web defined between the first andsecond adjacent signal conductors, or in combination with any one ormore of these descriptions.

The connector 50 achieves a differential insertion loss of less than −1dB at frequencies between approximately 1 GHz and approximately 25 GHz.The connector 50 achieves a differential insertion loss of less than −1dB at frequencies between approximately 1 GHz and approximately 33 GHz.A frequency domain near end crosstalk of the connector 50 is below −50dB at frequencies between approximately 1 GHz and approximately 34 GHz.A frequency domain near end crosstalk of the connector 50 is below −60dB at frequencies between approximately 1 GHz and approximately 31 GHz.A frequency domain far end crosstalk of the connector 50 is below −50 dBat frequencies between approximately 1 GHz and approximately 34 GHz. Afrequency domain far end crosstalk of the connector 50 is below −60 dBat frequencies between approximately 1 GHz and approximately 25 GHz.

FIGS. 26-29 illustrate a connector of a second preferred embodiment ofthe present invention. As shown in FIG. 26, the male connector 70includes a housing 71 and a lead frame 60 including a plurality ofcontact assemblies. As oriented in FIG. 26, the connector 70 can bemounted to a PCB with the contacts connected to traces of the PCB.

FIG. 27 illustrates one of the plurality of contact rows in the leadframe 60. As shown in FIG. 27, the contact row includes two separatecontact assemblies each including a wafer 61 of a dielectric material, aplurality of contacts 62 defined as adjacent differential pairs ofcontacts 72, and a conductive ground shield 65. It should be understoodthat the lead frame 60 can include one or any number of similarassemblies. As shown in FIG. 27, the plurality of differential pairs ofcontacts 62 are located between the wafer 61 and the ground shield 65,but other arrangements are also possible.

FIG. 28 illustrates another view of the contact row shown in FIG. 27.FIG. 28 shows a portion of the wafer 61 protruding through the groundshield 65 and the differential pairs of contacts 72 visible through anopening in the ground shield 65.

FIG. 29 illustrates a close-up of the view of the contact row of thelead frame 60 shown in FIG. 28. As shown through the opening in theground shield 65 in FIG. 29, there is a web 63 and a button 64 betweenthe contacts 62 of the adjacent differential pair of contacts 72. Asdescribed above, the web 63 and the button 64 can be extensions of thewafer 61 of dielectric material and used to adjust the spacing andimpedance between the contacts 72 to manage the crosstalk and couplingof signals. Also, FIG. 29 shows the tails 62 c of contacts 62 and tails65 c of the ground shield 65 used to solder the connector 70 to a PCB.Tabs 65 a can be included at portions of the ground shield 65 to defineportions of the ground shield 65 that can be connected with contacts ofthe mating connector, as further discussed below.

FIG. 30 illustrates a mating connector of the second preferredembodiment of the present invention. As shown in FIG. 30, the femaleconnector 90 includes a housing 91 and a lead frame 80 including aplurality of contact assemblies. As oriented in FIG. 30, the connector90 can be mounted to an electrical component such as a PCB, traces,cables, etc. When aligned, the female connector 90 of FIG. 30 can matewith the male connector 70 of FIG. 26 and connect two PCBs together.When mated, the ground contacts 93 and adjacent differential pair ofcontacts 92 of the female connector 90 make physical contact and anelectrical connection with corresponding portions of the ground shield65 and adjacent differential contacts 72 of the male connector 70.

FIG. 31 illustrates one of the plurality of contact rows in the leadframe 80. As shown in FIG. 31, the contact row includes two separatecontact assemblies each including a conductive ground shield 85 withcontacts 93, a wafer 81 of a dielectric material shown protrudingthrough the ground shield 85, and a plurality of contacts 82. It shouldbe understood that the lead frame 80 can include one or any number ofsimilar assemblies.

FIG. 32 illustrates another view of the contact row shown in FIG. 31. Asshown in FIG. 32, adjacent contacts 82 define a plurality ofdifferential pairs of contacts 92. The differential pairs of contacts 92are alternately located between sets of ground contacts 93 along the rowof contacts.

FIG. 33 illustrates a close-up of the view of the contact row of thelead frame 80 shown in FIG. 32. As shown, there is a web 83 and a button84 between the contacts 82 of the adjacent differential pair of contacts92. As discussed above, the web 83 and the button 84 can be extensionsof the wafer 81 and used to adjust the spacing and impedance between thecontacts 92 to manage the crosstalk and coupling of signals. Also, FIG.32 shows the tails 82 c of the contacts 92 and the tails 85 c of theground shield contacts 93 used to solder the connector 90 to a PCB.

Tips 85 b of alternating individual contacts 82 of the sets of groundcontacts 93 are bent in opposing directions to aid in contact andconnector retention when mated with the tabs 65 a of the ground shield65 of the male connector 70. Tips 82 b of the contacts 92 are bent indirections opposite to the corresponding tips of the contacts 72 in themale connector 70.

FIGS. 34 and 35 show a cage assembly 120 according to a preferredembodiment of the present invention. A transceiver (not shown) can beplugged into the opening 124 of the cage assembly 120. Any suitabletransceiver can be used. The cage assembly 120 is mounted to the PCB 126and includes a cage 121, a heatsink 122, and a cables 123. Any suitablesubstrate can be used instead of the PCB 126. FIG. 34 shows the cageassembly 120 with the heatsink 122, and FIG. 35 shows the cage assembly120 without the heatsink 122. The heatsink 122 is attached to the cage121 using a retention latch 127 and a clips 128 that allow the heatsink122 to float with respect to the cage 121. The retention latch 127 andthe clips 128 can provide a force that pushes the heatsink 122 intocontact with the transceiver when the transceiver is plugged into thecage assembly 120. It is possible to attach the heatsink 122 to the cage121 in any suitable manner. For example, the heatsink 122 can beattached to the cage 121 so that the heatsink does not float, i.e., theheatsink 122 is fixed relative to the cage 121. It is possible to useany suitable heat exchanger instead of heatsink 122, including, forexample, active heat exchangers such as a cold plate or a heat pipe.

A receptacle 125 is located within the cage 121 as shown in FIG. 35.Cables 123 can extend from the back of the cage 121 and can be connectedto the receptacle 125. The cables 123 can be referred to as “flyovercables” because the cables 123 make a direct electrical connectionbetween the receptacle 125 and a remote location on the PCB 126, i.e.the cables 123 flyover the PCB 126. Any suitable cables can be used forthe flyover cables 123, including, for example, twinaxial and coaxialcables. The cables 123 can include low-speed flyover cables andhigh-speed flyover cables.

The receptacle 125 is mounted to the PCB 126 and can include an openinginto which an edgecard of the transceiver can be inserted. FIGS. 36 and37 show the contacts 132 within the receptacle 125. Each of the contacts132 includes a beam 132 a, a tip 132 b, and a tail (not shown butconnected to a corresponding cable 123). The edgecard includes pads thatengage with the beams 132 a of the contacts 132. Reference number 132generally refers to all of the contacts, which include ground contacts143 and contacts 142 in a differential pair. The beams 132 a deflect asthe edgecard is inserted into the receptacle 125, creating a mechanicaland electrical connection between the contacts 132 and pads. An edgecardto be used with the receptacle 125 can include pads on the top andbottom surfaces that engage with the top row of contacts 132 and withthe bottom row of contacts 132. As shown in FIG. 37, the contacts 132can be arranged into four rows: a top-front row, a top-back row, abottom-front row, and a bottom-back row. The pads on the edgecard can bearranged into corresponding rows. This arrangement of contacts 132 andpads can be referred to as “double density.” It is possible to use otherarrangements of contacts 132 and pads, including, for example, top andbottom rows of contacts and corresponding top and bottom rows of pads.

In the receptacle 125, some contacts 132 can be directly connected tothe PCB 128 and other contacts 132 can be connected to the cables 123.The receptacle 125 can include press-fit tails or eye-of-the-needletails that can be inserted into corresponding holes in the PCB 126 tomount the receptacle 125 to the PCB 126. It is possible to mount thereceptacle to the intermediate PCB in other manners, including, forexample, surface-mount technology (SMT) or through-hole soldering.

As shown in FIGS. 36 and 37, the contacts 132 are included in wafers131. Each row of contacts 132 is included in its own wafer 131. A web133 fills at least a portion of the gap between the adjacent beams 132 aof the differential signal contacts 132. The web 133 can include abutton 134 toward the tips 132 b of the contacts 142. The button 134anchors the web 133 to the beams 132 a, allowing the web 133 to movewith the beams 132 a as the beams 132 a deflect. The web 133 keeps theadjacent contacts 142 spaced apart at a constant distance from eachother, even when the beams 132 a are deflected. The constant distancebetween adjacent contacts 142 improves the impedance matching.

Any description of a preferred embodiment disclosed herein can apply tothe other preferred embodiments disclosed herein. It should beunderstood that the foregoing description is only illustrative of thepresent invention. Various alternatives and modifications can be devisedby those skilled in the art without departing from the presentinvention. Accordingly, the present invention is intended to embrace allsuch alternatives, modifications, and variances that fall within thescope of the appended claims.

What is claimed is:
 1. An electrical connector comprising: a dielectrichousing; a first electrical contact carried by the dielectric housing,the first electrical contact defines a first contact surface; a secondelectrical contact carried by the dielectric housing and positionedadjacent to the first electrical contact to define a differential signalpair with the first electrical contact, the second electrical contactdefining a second contact surface electrically isolated from the firstcontact surface; and a dielectric material other than air that extendsonly between the first electrical contact and the second electricalcontact, the dielectric material other than air extends continuouslyfrom a point adjacent to the dielectric housing and terminates prior tothe first contact surface.
 2. The electrical connector of claim 1,wherein the dielectric material other than air is a web integral withthe dielectric housing.
 3. The electrical connector of claim 1, wherein,when a mating connector applies a force to the first contact surface andthe second contact surface, the first and second mating ends and thedielectric material other than air all move in a first direction.
 4. Theelectrical connector according to claim 1, further comprising adielectric button positioned only between the first and secondelectrical contacts.
 5. The electrical connector of claim 1, wherein thedielectric material other than air is cantilevered.
 6. The electricalconnector of claim 5, wherein the dielectric material other than air iscantilevered with respect to a pivot point adjacent to a dielectricwafer housing.
 7. An electrical connector comprising: first and secondadjacent electrical contacts that each define respective first andsecond mating ends, the first mating end of a first one of the first andsecond adjacent electrical contacts defines a first contact surface, thesecond mating end of a second one of the first and second adjacentelectrical contacts defines a second contact surface electricallyisolated from the first contact surface; a third electrical contact thatdefines a third mating end and that is positioned immediately adjacentto the second one of the first and second electrical contacts; and adielectric material other than air positioned between the first andsecond adjacent electrical contacts; wherein when a force is applied toone of the first contact surface and the second contact surface, thefirst and second mating ends and the dielectric material other than airall move in a first direction; and the electrical connector is devoid ofdielectric material other than air between the second mating end and thethird mating end.
 8. The electrical connector of claim 7, wherein thethird electrical contact is positioned edge-to-edge with the second oneof the first and second electrical contacts.
 9. The electrical connectoraccording to claim 7, wherein the first and second adjacent electricalcontacts are each cantilevered with respect to a dielectric waferhousing, and the dielectric material other than air is a web positionedbetween the first and second adjacent electrical contacts, the web iscantilevered with respect to a pivot point adjacent to the dielectricwafer housing such that the web also moves in the first direction when amating connector applies a force to the first contact surface and thesecond contact surface.
 10. The electrical connector according to claim7, further comprising: a first differential signal pair and a seconddifferential signal pair carried by a dielectric housing; and a groundshield positioned adjacent to the dielectric housing; wherein thedielectric housing defines a first air gap between the first and secondadjacent signal contacts of the first differential signal pair, a secondair gap between third and fourth adjacent signal contacts of the seconddifferential signal pair, and a third air gap between the second signalcontact and the third signal contact that exposes the ground shield toair between the second signal contact and the third signal contact. 11.The electrical connector according to claim 7, wherein the electricalconnector has a differential insertion loss of less than −1 dB atfrequencies between approximately 1 GHz and approximately 25 GHz. 12.The electrical connector according to claim 7, wherein the electricalconnector has a differential insertion loss of less than −1 dB atfrequencies between approximately 1 GHz and approximately 33 GHz. 13.The electrical connector according to claim 7, wherein a frequencydomain near end crosstalk is below −50 dB at frequencies betweenapproximately 1 GHz and approximately 34 GHz.
 14. The electricalconnector according to claim 7, wherein a frequency domain near endcrosstalk is below −60 dB at frequencies between approximately 1 GHz andapproximately 31 GHz.
 15. The electrical connector according to claim 7,wherein a frequency domain far end crosstalk is below −50 dB atfrequencies between approximately 1 GHz and approximately 34 GHz. 16.The electrical connector according to claim 7, wherein a frequencydomain far end crosstalk is below −60 dB at frequencies betweenapproximately 1 GHz and approximately 25 GHz.
 17. The electricalconnector according to claim 7, further comprising an electricalconnector housing; wherein the electrical connector housing does notdefine front ribs between the first and second mating ends of first andsecond adjacent signal conductors.
 18. The electrical connectoraccording to claim 7, wherein the dielectric material other than air iscantilevered.
 19. The electrical connector according to claim 7,wherein: the first and second adjacent electrical contacts each definetwo opposed edges; the first and second adjacent electrical contacts arepositioned edge-to-edge; and the first and second adjacent electricalcontacts are physically connected to one another adjacent to the firstand second mating ends by the dielectric material other than air. 20.The electrical connector according to claim 7, further comprising adielectric button positioned only between the first and second adjacentelectrical contacts.
 21. An electrical connector comprising anelectrical connector housing that carries first and second adjacentelectrical contacts in a first pair of electrical contacts and third andfourth adjacent electrical contacts in a second pair of electricalcontacts, wherein the first and second adjacent electrical contacts eachdefine respective first and second mating ends; the third and fourthadjacent electrical contacts each define respective third and fourthmating ends; and the electrical connector housing defines front ribsbetween the first and second pairs of electrical contacts, does notdefine front ribs between the first and second mating ends of the firstand second adjacent electrical contacts, and does not define front ribsbetween the third and fourth mating ends of the third and fourthadjacent electrical contacts.
 22. An electrical connector comprising: anelectrical connector housing that carries first and second adjacentelectrical contacts; a dielectric material other than air positionedbetween the first and second adjacent electrical contacts; and adielectric button positioned only between the first and second adjacentelectrical contacts; wherein the first and second adjacent electricalcontacts each define respective first and second mating ends, and theelectrical connector housing does not define front ribs between thefirst and second mating ends of the first and second adjacent electricalcontacts.
 23. The electrical connector of claim 22, further comprisingthird and fourth adjacent electrical contacts; wherein the first andsecond adjacent electrical contacts define a first pair of electricalcontacts; the first and second adjacent electrical contacts each definerespective first and second mating ends; the third and fourth adjacentelectrical contacts define a second pair of electrical contacts; thethird and fourth adjacent electrical contacts each define respectivethird and fourth mating ends; and the electrical connector housingdefines front ribs between the first and second pairs of electricalcontacts, and does not define front ribs between the third and fourthmating ends of the third and fourth adjacent electrical contacts.
 24. Anelectrical connector comprising: a dielectric housing; a firstelectrical contact carried by the dielectric housing, the firstelectrical contact defines a first contact surface; a second electricalcontact carried by the dielectric housing and positioned adjacent to thefirst electrical contact to define a differential signal pair with thefirst electrical contact, the second electrical contact defining asecond contact surface electrically isolated from the first contactsurface; a dielectric material other than air that extends between thefirst electrical contact and the second electrical contact, thedielectric material other than air extends continuously from a pointadjacent to the dielectric housing and terminates prior to the firstcontact surface; and a dielectric button positioned only between thefirst and second electrical contacts.
 25. The electrical connector ofclaim 24, wherein the dielectric material other than air is a webintegral with the dielectric housing.
 26. The electrical connector ofclaim 24, wherein, when a mating connector applies a force to the firstcontact surface and the second contact surface, the first and secondmating ends and the dielectric material other than air all move in afirst direction.
 27. The electrical connector according to claim 24,wherein: the first and second adjacent electrical contacts each definetwo opposed edges; the first and second adjacent electrical contacts arepositioned edge-to-edge; and the first and second adjacent electricalcontacts are physically connected to one another adjacent to the firstand second mating ends by the dielectric material other than air. 28.The electrical connector of claim 24, wherein the dielectric materialother than air is cantilevered.
 29. The electrical connector of claim28, wherein the dielectric material other than air is cantilevered withrespect to a pivot point adjacent to a dielectric wafer housing.
 30. Anelectrical connector comprising: first and second adjacent electricalcontacts that each define respective first and second mating ends, thefirst mating end of a first one of the first and second adjacentelectrical contacts defines a first contact surface, the second matingend of a second one of the first and second adjacent electrical contactsdefines a second contact surface electrically isolated from the firstcontact surface; a dielectric material other than air positioned betweenthe first and second adjacent electrical contacts; and a dielectricbutton positioned only between the first and second adjacent electricalcontacts; wherein when a force is applied to one of the first contactsurface and the second contact surface, the first and second mating endsand the dielectric material other than air all move in a firstdirection.
 31. The electrical connector of claim 30, further comprisinga third electrical contact positioned immediately adjacent to andedge-to-edge with the second one of the first and second electricalcontacts; wherein the electrical connector is devoid of dielectricmaterial other than air between the third electrical contact and thesecond one of the first and second adjacent electrical contacts.
 32. Theelectrical connector according to claim 30, wherein the first and secondadjacent electrical contacts are each cantilevered with respect to adielectric wafer housing, and the dielectric material other than air isa web positioned between the first and second adjacent electricalcontacts, the web is cantilevered with respect to a pivot point adjacentto the dielectric wafer housing such that the web also moves in thefirst direction when a mating connector applies a force to the firstcontact surface and the second contact surface.
 33. The electricalconnector according to claim 30, further comprising: a firstdifferential signal pair and a second differential signal pair carriedby a dielectric housing; and a ground shield positioned adjacent to thedielectric housing; wherein the dielectric housing defines a first airgap between the first and second adjacent signal contacts of the firstdifferential signal pair, a second air gap between third and fourthadjacent signal contacts of the second differential signal pair, and athird air gap between the second signal contact and the third signalcontact that exposes the ground shield to air between the second signalcontact and the third signal contact.
 34. The electrical connectoraccording to claim 30, wherein the electrical connector has adifferential insertion loss of less than −1 dB at frequencies betweenapproximately 1 GHz and approximately 25 GHz.
 35. The electricalconnector according to claim 30, wherein the electrical connector has adifferential insertion loss of less than −1 dB at frequencies betweenapproximately 1 GHz and approximately 33 GHz.
 36. The electricalconnector according to claim 30, wherein a frequency domain near endcrosstalk is below −50 dB at frequencies between approximately 1 GHz andapproximately 34 GHz.
 37. The electrical connector according to claim30, wherein a frequency domain near end crosstalk is below −60 dB atfrequencies between approximately 1 GHz and approximately 31 GHz. 38.The electrical connector according to claim 30, wherein a frequencydomain far end crosstalk is below −50 dB at frequencies betweenapproximately 1 GHz and approximately 34 GHz.
 39. The electricalconnector according to claim 30, wherein a frequency domain far endcrosstalk is below −60 dB at frequencies between approximately 1 GHz andapproximately 25 GHz.
 40. The electrical connector according to claim30, further comprising an electrical connector housing; wherein theelectrical connector housing does not define front ribs between thefirst and second mating ends of first and second adjacent signalconductors.
 41. The electrical connector according to claim 30, whereinthe dielectric material other than air is cantilevered.
 42. Theelectrical connector according to claim 30, wherein: the first andsecond adjacent electrical contacts each define two opposed edges; thefirst and second adjacent electrical contacts are positionededge-to-edge; and the first and second adjacent electrical contacts arephysically connected to one another adjacent to the first and secondmating ends by the dielectric material other than air.